package org.shj.netty.chartper2.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Date;
import java.util.Iterator;
import java.util.Set;

public class MultiplexerTimeServer implements Runnable{
	private Selector selector;
	
	private ServerSocketChannel servChannel;
	
	private volatile boolean stop;
	
	public MultiplexerTimeServer(int port){
		try{
			selector = Selector.open();
			
			servChannel = ServerSocketChannel.open();
			servChannel.configureBlocking(false);
			servChannel.socket().bind(new InetSocketAddress(port), 1024);
			servChannel.register(selector, SelectionKey.OP_ACCEPT);
			System.out.println("The time server is start in port: " + port);
		}catch(IOException e){
			e.printStackTrace();
			System.exit(1);
		}
	}
	
	public void stop(){
		this.stop = stop;
	}
	
	public void run(){
		while(!stop){
			try{
				selector.select(1000);
				Set<SelectionKey> selectedKeys = selector.selectedKeys();
				Iterator<SelectionKey> it = selectedKeys.iterator();
				SelectionKey key = null;
				
				while(it.hasNext()){
					key = it.next();
					it.remove();
					try{
						handleInput(key);
					}catch(Exception e){
						e.printStackTrace();
						if(key != null){
							key.cancel();
							if(key.channel() != null)
								key.channel().close();
						}
					}
				}
			}catch(Throwable t){
				t.printStackTrace();
			}
		}
		
		//多路复用器关闭后，所有注册在上面的Channel和Pipe等资源都会被自动去注册并关闭，所以不需要重复释放资源 
		if(selector != null){
			try{
				System.out.println("selector.close()");
				selector.close();
				
			}catch(IOException e){
				e.printStackTrace();
			}
		}		
	}
	
	private void handleInput(SelectionKey key) throws IOException{
		System.out.println("handleInput()");
		if(key.isValid()){
			//处理新接入的请求消息
			if(key.isAcceptable()){
				System.out.println("key.isAcceptable()");
				//Accept the new connection
				ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
				SocketChannel sc = ssc.accept();
				sc.configureBlocking(false);
				
				//Add the new connection to the selector
				sc.register(selector, SelectionKey.OP_READ);
			}
			
			if(key.isReadable()){
				System.out.println("key.isReadable()");
				//Read the data
				SocketChannel sc = (SocketChannel) key.channel();
				ByteBuffer readBuffer = ByteBuffer.allocate(1024);
				int readBytes = sc.read(readBuffer);
				
				if(readBytes > 0){
					System.out.println("readBytes > 0");
					readBuffer.flip();
					
					byte[] bytes = new byte[readBuffer.remaining()];
					readBuffer.get(bytes);
					
					String body = new String(bytes, "UTF-8");
					System.out.println("The time server receive order: " + body);
					
					String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body) ? new Date(System.currentTimeMillis()).toString() : "Bad Order";
					doWrite(sc, currentTime);
					
				}else if(readBytes < 0){	
					System.out.println("readBytes < 0");
					//对端链路关闭
					key.cancel();
					sc.close();
					
				}else {
					//读到 0 字节，忽略
				}	
			}
		}
	}
	
	private void doWrite(SocketChannel channel, String response) throws IOException{
		System.out.println("doWrite()");
		if(response != null && response.trim().length() > 0){
			byte[] bytes = response.getBytes();
			ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
			writeBuffer.put(bytes);
			writeBuffer.flip();
			channel.write(writeBuffer);
		}
	}
}
